Refillable Syringe Ratchet Mechanism for Precise Dosing

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Solution Overview

Problem

Existing syringes with barrel and plunger formations face issues such as difficulty in refilling due to a 'suck back' action, leading to precision problems and waste, especially when administering substances like botulinum toxin, which can result in economic and environmental concerns.

Innovation Solution

A syringe design with a plunger and barrel that allows for a ratchet-like feedback mechanism during fluid expulsion while enabling easy refilling by disengaging the barrel formation from plunger formations, using a resilient part or spring to bias the barrel formation, and a rotatable plunger with graduated markings for precise dosing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cooperating formations are formed to provide a 'suck back' action during use, then fluid retention is improved, but the ease of operation deteriorates due to difficulty in pulling the plunger backwards

Engineering Contradiction:
Improvefluid retentionVSAvoidease of refilling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The syringe transitions from a static engagement state during injection to a dynamic disengaged state during refilling. The resilient barrel formation automatically engages with plunger formations during the injection phase to provide suck-back prevention, then can be manually disengaged to allow free plunger movement for refilling, adapting its behavior to the operational phase.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The interaction between barrel formation and plunger formations is segmented into distinct operational phases: engagement phase for injection (providing ratchet-like feedback and suck-back prevention) and disengagement phase for refilling (allowing free plunger movement). This segmentation allows each phase to have optimized characteristics without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the barrel formation and plunger formations are engaged to provide ratchet-like feedback, then dosing precision is improved, but the ease of operation worsens due to extra force needed to pull back the plunger

Engineering Contradiction:
Improvedosing precisionVSAvoidease of refilling
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The engagement between barrel formation and plunger formations is made dynamic rather than permanent. During the dosing phase, the formations are engaged to provide ratchet-like feedback and precise dosing control. During the refilling phase, the engagement is disengaged to allow free plunger movement, eliminating the force barrier while preserving the dosing precision capability when needed.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the plunger is constrained to prevent unintentional fluid expulsion, then fluid retention is improved, but the ease of operation deteriorates due to reduced precision in fluid intake

Engineering Contradiction:
Improvefluid retentionVSAvoidprecision of fluid intake
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The plunger's movement control is segmented into two distinct modes: constrained movement during injection (with ratchet-like feedback from barrel-plunger formation engagement) for precise dosing and fluid retention, and unconstrained movement during refilling (when formations are disengaged) for precise fluid intake. This segmentation allows each mode to have optimized control characteristics.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Provides audible and tactile feedback for precise dosing, prevents fluid waste, and allows easy refilling, enhancing user control and reducing errors in administering substances like botulinum toxin.

Implementation Method 1

using a resilient part or spring to bias the barrel formation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3432950B1syringe
Publication Date: 2026.03.04 VLOW MEDICAL
  • EP3432950B1 patent drawingFigure 1A~1B
  • EP3432950B1 patent drawingFigure 1C~1E
  • EP3432950B1 patent drawingFigure 2

AI summary

Syringe The disclosure relates to a syringe (1), comprising a barrel (2) and a plunger (3), wherein at least a part of said plunger (3) is longitudinally slidably received in the barrel (2), wherein the plunger (3) comprises a portion that is provided with at least one series of interspaced plunger formations (33), wherein the barrel (2) is provided with a corresponding barrel formation (27) for consecutively engaging successive ones of the plunger formations (33), wherein the syringe (1) is arranged such as to be brought from a first state in which the barrel formation (27) successively engages the plunger formations (33) during slidable displacement of the plunger (3) within the barrel (2), into a second state in which the barrel formation (27) is held in a position spaced away from the plunger portion that comprises the plunger formations (33).